WAC 296-307-36836. Use of fixture wires

(1) A fixture wire must be approved for the voltage, temperature, and location of use. A fixture wire used as a grounded conductor must be identified. (2) Fixture wires may be used: (a) For installation in lighting fixtures and in similar equipment where enclosed or protected and not subject to bending or twisting in use; or (b) For connecting lighting fixtures to the branch-circuit conductors supplying the fixtures. (3) Fixture wires must not be used as branch-circuit conductors except as permitted for Class 1 power limited circuits.